Experiments upon Diamond, Anthracite and Piumbago. 349 
success. I have made various attempts, which have failed, 
and after losing two diamonds, the fragments being thrown 
about with a strong decrepitation, I have desisted from the 
attempt, having, as I conceive, a more feasible project in 
view. ; ; 
J trust you will not consider the details of the preceding 
pages, as being too minute, provided the subject appears to 
you as interesting as it does to me. The fusion ws charcoal 
and of plumbago, is sufficiently remarkable, but the evident 
approximation of the material of these bodies towards the 
condition of diamond, from which they differ so remarkably 
in their physical properties, affords if | mistake not, a strik- 
ing confirmation of some of our leading chemical doctrines. 
remain as ever your faithful friend and servant, 
B. SILLI 
MAN. 
Art. XXI.—Experiments upon Diamond, Anthracite and 
Plumbago with the compound Blow Pipe, in a letter ad- 
dressed to Prof. Robert Hare, M. D. by the Editor. 
Yale College, April 15, 1823. 
My Dear Sir, 
Having last year, caused to be constructed, an apparatus, 
capable of containing fifty-two gallons of gas, for the supply 
of your compound, or, oxy-hydrogen blow pipe, and capable 
of receiving a strong impulse from pressure, | have been in- 
tending as soon as practicable, to subject the diamond, and 
the anthracite to its intense beat. Although their being non- 
conductors, would be no impediment to the action of the 
blow pipe flame on them, still, obvious considerations. have 
always made me consider the success of such experiments, 
as very doubtful. I allude of course, to the combustibility 
of these bodies, from which we might expect, that they 
would be dissipated by a flame, sustained by oxygen gas. 
My first trials were made by placing small diamonds in a 
cavity in charcoal, but the support was, in every instance, so 
rapidly consumed, that the diamonds were speedily displa- 
ced, by the current of gas. I next made a chink ina peice of 
solid quick lime, and crowded the diamond into it; this proved 
avery good support, but the effulgence of light was so daz- 
